{	Problem: http://codeforces.ru/problemset/problem/27/A
	Verdict: Accepted

}
var n,i,k:longint; b:array[1..3001] of boolean;
begin
fillchar(b,sizeof(b),false);
read(n);
for i:=1 to n do begin
    read(k);
    b[k]:=true;
end;
i:=1;
while b[i] do inc(i);
write(i);
end.